Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 30)

3. Personal488/AT I. HARDWARE GUIDES
I-14 Personal488 User’s Manual, Rev. 3.0
I/O Base Address Selection
The I/O base address sets the addresses used by the computer to communicate with the IEEE 488
interface hardware on the board. The address is normally specified in hexadecimal and can be
02E1 ,
22E1 , 42E1 , or 62E1 . The registers of the IOT7210 IEEE 488 controller chip and other auxiliary
registers are then located at fixed offsets from the base address.
Most versions of Driver488 are capable of
managing as many as four IEEE 488 interface
boards. To do so, the board configurations
must be arranged to avoid conflict among
themselves. No two boards may have the
same I/O address, but they may, and usually
should, have the same DMA channel and
interrupt level.
The factory default I/O base address is 02E1 .
To use a different base address, set S2
according to the figure.
I/O Base Address Register
02E1 22E1 42E1 62E1 Read Register Write Register
02E1 22E1 42E1 62E1 Data In Data Out
06E1 26E1 46E1 66E1 Interrupt Status 1 Interrupt Mask 1
0AE1 2AE1 4AE1 6AE1 Interrupt Status 2 Interrupt Mask 2
0EE1 2EE1 4EE1 6EE1 Serial Poll Status Serial Poll Mode
12E1 32E1 52E1 72E1 Address Status Address Mode
16E1 36E1 56E1 76E1 CMD Pass Through Auxiliary Mode
1AE1 3AE1 5AE1 7AE1 Address 0 Address 0/1
1EE1 3EE1 5EE1 7EE1 Address 1 End of String
Interrupt Selection
The AT488 interface board may be set to interrupt the PC on the occurrence of certain hardware
conditions. The main board interrupt may be set to IRQ level 3 through 7, 9 through 12, 14, or 15.